e.g. like so (pretty old code but the principle should be clear)
```rust
#[cfg(feature = "spi")]
pub type WsSpi = Spi<SPI1, (NoSck, NoMiso, Pin<'B', 5_u8, Alternate<5_u8>>), TransferModeNormal>;

#[cfg(all(not(feature = "spi"), feature = "spi_alt"))]
pub type WsSpi = Spi<SPI2, (NoSck, NoMiso, Pin<'B', 15_u8, Alternate<5_u8>>), TransferModeNormal>;

pub type WS = Ws2812<WsSpi>;
```